1. Field of the Invention
The present invention relates generally to flow control devices for use in liquid cooled engines. More particularly, the invention concerns a flow control element which can be used in place of conventional thermostat units of the character typically provided in cooling systems for internal combustion engines.
2. Discussion of the Prior Art
As a general rule, internal combustion engines are cooled by the circulation of a liquid coolant through the block and head of the engine and through a radiator. Air is drawn through the radiator by a fan driven by the engine and by the motion of the vehicle as the vehicle moves along the highway. The heat from the liquid coolant is thus dissipated by the air flowing past the radiator. In recent years cooling systems comprise a sealed system adapted to be operated under pressure. Increased pressure in the system raises the boiling point of the liquid and accordingly, raises the operating temperature at which the coolant may be maintained during operation of the system.
When the cooling system of the internal combustion engine of the character found in the typical automobile is operated under pressure, the thermostat performs the function of controlling the rate of circulation of coolant within the system in accordance with the temperature of the coolant. More particularly, the thermostat is adapted to reduce the amount of coolant flowing through the cooling system when the coolant has reached a predetermined low temperature. In this low temperature operating mode, the engine is capable of operating at peak efficiency without a large volume of coolant flowing through the system. Conversely, when the coolant reaches a predetermined high temperature, the thermostat opens to enable a larger volume of coolant to flow through the cooling system to maintain optimum engine performance.
Many parts of the United States experience wide temperature variations from season to season. When the automobile must perform during the winter months at sub-zero temperatures and during the summer months at very high ambient temperatures, use of the thermostat is extremely important. In conditions of widely varying ambient temperatures, the thermostat performs the vital function of controlling the rate of flow of coolant in a manner to insure peak performance of the internal combustion engine regardless of the outside temperature. However, in moderate climates, where outside temperatures are usually high and the temperature variations are slight from season to season, the thermostat plays a much less important role, since the thermostat normally functions in an open condition.
A major problem inherent in many prior art thermostat units is the fact that when the unit fails, it typically fails in a closed condition. When the thermostat fails in this manner, inadequate fluid flow through the cooling system can result in serious damage to the engine from overheating. Because of this troublesome deficiency of prior art thermostats, individuals living in moderate climates often remove the thermostat entirely from the cooling system of the automobile. Because the thermostat does not perform a critical function in moderate climates, removal of the thermostat provides a safeguard against catastrophic overheating of the internal combustion engine should the thermostat fail in a closed condition. However, when the thermostat is removed entirely from the cooling system, the normal flow of fluid through the cooling system is altered because the thermostat itself, even in an open condition, provides a restriction to the flow of fluid through the cooling system.
The primary purpose of the replacement element of the present invention is to permit removal of the thermostat from the cooling system of the automobile while still maintaining the proper rate of fluid flow through the coolant system of the particular vehicle.
Maintaining the proper rate of flow of coolant through the cooling system is essential to accomplishing optimum vehicle performance. For example, if the thermostat is removed and the device of the present invention is not installed, the coolant will flow through the radiator to rapidly permit proper cooling. Therefore, in the warmer part of the year the engine will tend to run too hot. By implanting the device of the invention into the cooling system, however, fluid flow will be slowed to permit optimum cooling of the fluid by the radiator. Conversely, during the cooler part of the year, the coolant will move too rapidly through the radiator and the engine will tend to run too cool. This is both harmful to engine performance and also prevent the vehicle heating system from functioning properly. By installing the device of the invention into the vehicle system in place of the thermostat, the rate of flow of fluid is reduced to allow the fluid to heat properly during the cooler months and to permit the heater to operate properly.
As will be better understood from the description which follows, the replacement element of the present invention is adapted to seat within the coolant system in the same location as the thermostat unit. Because of its novel construction, the device can be constructed to closely replicate high temperature restriction to fluid flow through the cooling system provided by the thermostat recommended for use with the particular automobile. More specifically, the replacement element of the present invention can be provided with a plurality of fluid flow apertures strategically sized and located so as to closely replicate the fluid flow characteristic of the fully open thermostat of the character installed as standard equipment in the particular vehicle.